[R] use of quotation marks

[Rodrigo Briceño]

Dear R Users. I just discovered today a problem in the use of
quotation marks when I'm doing some programs in R. I'm using windows
vista environment.
The programs that I wrote in the University, made in Windows XP
machines run perfectly, but when I run those in my laptop with VISTA,
there are many errors. Those errors are due to the type of quotation
marks.
In the university the quotation marks appear inclined (talking about
position), but in Vista quotation marks are totally vertical. So my
question is how to avoid this issue? Is there an specific font format
that I need to use to avoid those problems???

Thanks in advance for the help.